The Andhra Pradesh government is about to take a decision to prefer tunnel technology over conventional methods, for affordable housing. As per the report, many contractors are already using the technology, across the country. So what is this technology and how can you benefit from it?

What is Tunnel Technology?
The tunnel construction technique was developed almost 50 years ago. This technology can be used not only for residential projects, but for commercial projects as well. The three videos below describe the technology.

Video 1: https://www.youtube.com/watch?v=a9YKLuDoDx0
Video 2: https://www.youtube.com/watch?v=j-mhyj93cpQ
Video 3: https://www.youtube.com/watch?v=ODoH6JqJiAo

In this method, floor and walls of one floor of a building are cast together in one day. The entire building envelope as well as internal walls are made using concrete. The placement and remove of formwork for casting walls and floors is completely mechanized with cranes. Further, reinforcement steel is placed before placement of formwork. Once one floor is completed, the formwork is removed and placed for casting of floor above. Each formwork is in form of an inverted ‘L’, which are joined to get the desired shape. The formwork used in this technology are of superior quality, and reused multiple times till structure is complete. The curing process can be hastened by using heaters; the casting of floor above can take place the very next day.

The tunnel technology for housing is an effective way for building affordable structures quickly, with few number of skilled labour. It gives a strong cellular structure that can comply with all local regulations. Further, walls and floors have good finish, doing away with the need for further preparatory work for painting. A coat of gypsum plaster is enough for starting painting. The openings for doors, windows and electricals can also be built into the formwork; thereby reducing time for completing the building.

References
http://www.world-housing.net/WHEReports/wh100104.pdf
http://theconstructor.org/concrete/tunnel-construction-technique/8574/
http://tunnelformconstruction.com/tunnel%20form.htm